"I was shocked to see the new AAT member sitting in judgement on people:"
Welcome to the "justice" system of Australia... While not commenting on the example above as I'm not overly familiar with that case, you do see on many occasions lawyers with marginal ethics/behaviour appointed as judges or other high legal office positions). At least three spring to mind over here in the West.
I'm looking forward to the day a Judge Rayney is appointed (only those in WA will understand that sorry).
VH-MLE